It is well known in the photographic art to use compounds that upon reaction with oxidized developer, release inhibitors of silver development. This not only controls tone scale (the amount of density produced for the amount of light exposure) but also can lead to substantial improvements in image structure and color reproduction. Grain and granularity are improved by allowing for partial grain development so that more centers can be obtained. Acutance and sharpness are improved by the well-known masking effect caused by interlayer inhibitor diffusion. Color reproduction is improved via interlayer diffusion of the inhibitor via reduced development in one color record as a function of the amount of exposure in another.
Many different types of development inhibitor releasing compounds that rely on coupling reactions with oxidized developer (Dox) are known. In general, those that release the inhibitor directly upon reaction with Dox and have the inhibitor fragment directly bonded to the Dox reaction site are referred to as DIRs (development inhibitor releasers). Those materials that release the inhibitor indirectly and have an unstable intermediate group between coupling site and the inhibitor fragment are generally referred to as DIARs (development inhibitor assisted releasers). These unstable intermediate groups are typically referred to as timing or switching groups and delay the introduction of the free inhibitor moiety. Each of these types of image modifier has advantages and disadvantages and the choice is usually determined by the requirements of the particular film element.
2-Substituted-5-amino-1-napthol derivatives are well known in the photographic art as cyan couplers. For example, see U.S. Pat. Nos. 4,690,889, 4,883,746, EP 307,927B1 and Research Disclosure (1988), 290 367–70. It is well known to use this type of coupler to release PUGs (photographically useful groups) upon reaction with oxidized developer. For example, see U.S. Pat. No. 5,112,730. In particular, it is known to use this type of coupler to release inhibitors of silver development. For example, see EP 161,626, EP 572,887 and DE 3,635,391.
In general, the nature of the 2-substituent in these 5-amino-1-napthol compounds is widely disclosed and not limited to any particular type. However, it is commonly found that 2-carbamoyl groups are often useful and in particular, N-alkyl-2-carbamoyl groups, where the N-alkyl contains a sufficient number of atoms to limit diffusion of the coupler and subsequently formed cyan dye within the photographic film, are desirable.
JP08320541 A2 describes 2-N-arylcarbamoyl-5-amino-1-napthol couplers where the N-aryl contains an ortho-alkyloxy group in addition to other alkyl or alkyloxy groups. JP2001163847A2 describes the preparation of a wide number of 2-N-arylcarbamoyl-5-amino-1-napthol couplers. JP07140606 and JP07036158 describe a 2-N-(4-sulfamoylphenyl)carbamoyl-5-amino-1-napthol that indirectly releases an inhibitor of silver development via a timing group.
JP2003075970 and JP2000171933 describe the use of 2-chloro-5-amino-1-napthol derivatives, among others, for use in thermally developable imaging systems. JP07281371 describes the use of various 2-(N-alkyl, aryl and unsubstituted)carbamoyl-5-amino-1-napthols as cyan image couplers. JP07287367 describes the use of similar 2-(N-unsubstituted)carbamoyl couplers for the same purpose.
U.S. Pat. Nos. 6,107,016, 6,194,131, 6,437,169 and JP2002006456 all describe the use of 2-substituted-5-amino-1-napthols where the 5-amino group is substituted with an inhibitor of silver developer such that the inhibitor can be released via an intramolecular cyclization upon reaction with oxidized developer. Such materials do not form permanent cyan dyes.
In conventional photographic systems using a color negative origination material and a color print material, the dye formed from the cyan coupler used in the negative typically has a maximum absorbtivity at approximately 690 nm where the print has maximum red light sensitivity. However, for some purposes, it may be desirable to form cyan dyes in the negative that are substantially hypsochromic of 690 nm and closer to where the human eye perceives red light (˜610–640 nm). Known 2-substituted-5-amino-1-napthol derived dyes for color negative films typically have maximum absorbance at ˜690 nm.
Despite a large number of attempts to provide DIRs with desirable photographic performance, there still remains a need for DIRs with improved properties. The problem remains to provide a conventional silver halide photographic element having the desired tone scale with improved image structure and excellent color reproduction.